In surgical interventions, medical viewing instruments are often used that provide an image of an operating site. In this way, for example, it is possible to obtain an enlarged view of the operating site or, in the case of endoscopic operations, a view of the inside of the body. Moreover, these viewing instruments can make the intervention less tiring and/or can improve the awareness of the operating surgeon and, if appropriate, of further personnel, and they can allow the image to be recorded, for example for documentation purposes.
It is known, for example, to use an endoscope to obtain an endoscopic image of a cavity within the body in which a surgical intervention is performed. Endoscopes typically comprise a rigid or flexible elongate shaft, which is suitable for insertion into the cavity and at the distal end area of which (i.e. the area remote from the observer) an objective lens is provided for generating an image of an object field in the cavity. At the proximal end of the endoscope (i.e. the end near the observer), there is often an electronic camera for recording the image conveyed through the shaft to the proximal end via an image carrier. Since there is generally insufficient light in the observed cavity, the required illumination light is usually generated in the proximal end area of the endoscope, or coupled into the latter, and carried through the shaft to the distal end.
Moreover, surgical microscopes are known with which it is possible to generate an enlarged image of an operating site during open surgery. A surgical microscope also often has an electronic camera and an illuminating device. DE 10 2011 054 031 A1 discloses a device for viewing and illuminating an object field on a patient from a position set apart from the patient's body, which device has, at the distal end of a shaft, a head part that is widened in relation to the shaft and that has illumination for lighting purposes and has a lens system for viewing the object field, wherein the image taken is conveyed to a proximal end of the shaft, where a video camera can be coupled. A device of this kind with which an operating site can be illuminated and viewed in a surgical intervention from a working distance of 25 to 75 cm, for example, is designated as an exoscope. Exoscopes of this type are sold under the name VITOM® by Karl Storz GmbH & Co. KG. To hold a surgical microscope or an exoscope in a suitable position with respect to the operating site, a holding arrangement can be provided which can have an articulated arm that can be adjusted and fixed according to the specific requirements.
The instruments used in a surgical operation in a sterile area must be sterile. This cannot always be completely guaranteed in the case of the aforementioned viewing instruments, particularly if they comprise an electronic camera, since they are often not suitable for all sterilization methods, for example for autoclaving. It is therefore known for viewing instruments of this kind, or for the not completely sterile parts of the viewing instruments, to be covered with a sterile sleeve. Such a sterile sleeve or “drape” prevents microorganisms passing from the not completely sterile part of the viewing instrument to the operating area. In particular, the sterile sleeve ensures that, upon contact with a not completely sterile instrument, microorganisms are not transferred to surfaces or materials coming into contact with the operating site.
It is known from DE 202 21 380 U1 that a surgical microscope system for use in a sterile working atmosphere is covered partially with a sterile drape. The space enclosed by the drape is sealed off by means of a flange on an arm of the microscope stand. A suction unit, which contains a pump, can be provided for removal of medium from the drape. After the sterile drape has been arranged around the surgical microscope and has been secured by means of the flange on the arm of the stand, the space enclosed by the drape has air removed by the pump. To permit simple and rapid exchange of the drape between two surgical interventions, the drape can be ventilated by operating the pump in a reverse state, in which air is pumped from outside into the area enclosed by the drape.
Medical viewing instruments of the type described, in particular endoscopes, exoscopes and surgical microscopes, have components that heat during the use of the viewing instrument and emit heat to their surroundings. Examples of such components are electronic cameras and, if appropriate, light sources or light attachments integrated into the viewing instrument. If such a heat-emitting component of the viewing instrument is surrounded by a sterile sleeve, the emission of heat from the component to the environment is restricted or no longer possible. This can result in an overheating of the component in question, which may lead to reduced image quality and/or may damage the component in question or reduce its useful life.